Balloons intended for use within a mammalian body, such as a human, are employed in a variety of medical procedures, including dilation of narrowed blood vessels, placement of stents and other implants, temporary occlusion of blood vessels, drug delivery, thrombectomy, embolectomy, angioplasty, other endovascular procedures, and other procedures within a lumen of a mammalian body such as a human body. In this regard, as used herein, the term “body” can comprise a mammalian body such as a human body or other animal body.
In a typical application, a balloon (often coupled with a catheter or guidewire) is advanced to the desired location in the vascular system or other lumen of the body. The balloon is then hydraulically expanded in accordance with a medical procedure. Thereafter, the pressure is removed from the balloon, allowing the balloon to contract and permit removal of the catheter and, in many cases, the balloon.
Procedures such as these are generally considered minimally invasive, and are often performed in a manner which minimizes disruption to the patient's body. As a result, balloons are often inserted from a location remote from the region to be treated. For example, during angioplasty procedures involving coronary vessels, the balloon catheter is typically inserted into the femoral artery in the groin region of the patient, and then advanced through vessels into the coronary region of the patient. These catheters typically include some type of radiopaque marker to allow the physician performing the procedure to monitor the progress of the catheter through the body.
Non-compliant balloons employ a balloon made of relatively strong but generally non-porous and inelastic material (e.g., nylon, polyester, etc.) folded into a compact, small diameter cross section. These relatively stiff balloons are used to compact hard deposits in vessels. Due to the need for strength and stiffness, these devices are rated to employ high inflation pressures, usually up to about 8 to about 30 atmospheres depending on balloon diameter and specific need. They tend to be self-limiting as to diameter in that they will normally distend up to the rated (nominal) diameter and not distend appreciably beyond this diameter.
Once a conventional, non-compliant balloon is inflated to its self-limiting diameter, the application of additional pressure can cause rupture of the balloon, creating a hazardous condition. Thus, the pressure within a conventional, non-compliant balloon must be carefully monitored during use.
In addition, conventional, non-compliant balloons are made to be fluid tight (that is, without holes, openings, or pores) in order to achieve and maintain the typically high pressures of the intended application. Therefore, a typical non-compliant balloon will not provide a feature whereby fluid can be transferred from inside the balloon, through the balloon wall, to regions outside the balloon. Thus, for example, conventional, non-compliant balloons are not suitable for the delivery of a therapeutic agent via perfusion. Similarly, other desirable results of perfusion cannot be realized. As can be appreciated, there can be other problems associated with the use of conventional, non-compliant balloons.
Thus, there is a need for systems and methods that address one or more of the problems associated with conventional, non-compliant balloons. For example, there is a need for systems and methods for non-compliant balloons that are not susceptible to failure (e.g., rupture) at a wide pressure range. Likewise, there is a need for systems and methods for non-compliant balloons that can function to become selectively porous and provide localized perfusion and/or therapeutic agent delivery. In addition, there is a need for non-compliant balloons capable of luminal distention or occlusion over a wide pressure range and concomitantly provide for the selective, controlled transfer of fluids from balloon to regions external to the balloon.